From 5f735d6fce10b4552b0a6d3eb6503c5a302f4f61 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Thu, 23 Apr 2015 18:47:24 +0300
Subject: [PATCH] cmd, eth, p2p, p2p/discover: init and clean up the seed cache

---
 cmd/bootnode/main.go  |  2 +-
 eth/backend.go        |  2 ++
 p2p/discover/node.go  |  4 ++++
 p2p/discover/table.go | 16 +++++++++++++---
 p2p/discover/udp.go   |  8 ++++----
 p2p/server.go         |  6 +++++-
 6 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/cmd/bootnode/main.go b/cmd/bootnode/main.go
index dda9f34d4..26912525d 100644
--- a/cmd/bootnode/main.go
+++ b/cmd/bootnode/main.go
@@ -71,7 +71,7 @@ func main() {
 		}
 	}
 
-	if _, err := discover.ListenUDP(nodeKey, *listenAddr, natm); err != nil {
+	if _, err := discover.ListenUDP(nodeKey, *listenAddr, natm, ""); err != nil {
 		log.Fatal(err)
 	}
 	select {}
diff --git a/eth/backend.go b/eth/backend.go
index 356e7fd1a..382cfc832 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -179,6 +179,7 @@ func New(config *Config) (*Ethereum, error) {
 	if err != nil {
 		return nil, err
 	}
+	seedDbPath := path.Join(config.DataDir, "seeds")
 
 	// Perform database sanity checks
 	d, _ := blockDb.Get([]byte("ProtocolVersion"))
@@ -243,6 +244,7 @@ func New(config *Config) (*Ethereum, error) {
 		NAT:            config.NAT,
 		NoDial:         !config.Dial,
 		BootstrapNodes: config.parseBootNodes(),
+		SeedCache:      seedDbPath,
 	}
 	if len(config.Port) > 0 {
 		eth.net.ListenAddr = ":" + config.Port
diff --git a/p2p/discover/node.go b/p2p/discover/node.go
index d8a5cc351..3e79ddb53 100644
--- a/p2p/discover/node.go
+++ b/p2p/discover/node.go
@@ -387,3 +387,7 @@ func (db *nodeDB) add(id NodeID, addr *net.UDPAddr, tcpPort uint16) *Node {
 	db.update(n)
 	return n
 }
+
+func (db *nodeDB) close() {
+	db.ldb.Close()
+}
diff --git a/p2p/discover/table.go b/p2p/discover/table.go
index ba2f9b8ec..3702a2114 100644
--- a/p2p/discover/table.go
+++ b/p2p/discover/table.go
@@ -11,6 +11,9 @@ import (
 	"sort"
 	"sync"
 	"time"
+
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
 )
 
 const (
@@ -58,8 +61,14 @@ type bucket struct {
 	entries    []*Node
 }
 
-func newTable(t transport, ourID NodeID, ourAddr *net.UDPAddr) *Table {
-	db, _ := newNodeDB("", Version)
+func newTable(t transport, ourID NodeID, ourAddr *net.UDPAddr, seedCache string) *Table {
+	// Load the bootstrap seed cache (use in memory db upon failure)
+	db, err := newNodeDB(seedCache, Version)
+	if err != nil {
+		glog.V(logger.Warn).Infoln("Failed to open bootstrap seed cache:", err)
+		db, _ = newNodeDB("", Version)
+	}
+	// Create the bootstrap table
 	tab := &Table{
 		net:       t,
 		db:        db,
@@ -81,9 +90,10 @@ func (tab *Table) Self() *Node {
 	return tab.self
 }
 
-// Close terminates the network listener.
+// Close terminates the network listener and flushes the seed cache.
 func (tab *Table) Close() {
 	tab.net.close()
+	tab.db.close()
 }
 
 // Bootstrap sets the bootstrap nodes. These nodes are used to connect
diff --git a/p2p/discover/udp.go b/p2p/discover/udp.go
index 07a1a739c..c26703f19 100644
--- a/p2p/discover/udp.go
+++ b/p2p/discover/udp.go
@@ -144,7 +144,7 @@ type reply struct {
 }
 
 // ListenUDP returns a new table that listens for UDP packets on laddr.
-func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface) (*Table, error) {
+func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface, seedCache string) (*Table, error) {
 	addr, err := net.ResolveUDPAddr("udp", laddr)
 	if err != nil {
 		return nil, err
@@ -153,12 +153,12 @@ func ListenUDP(priv *ecdsa.PrivateKey, laddr string, natm nat.Interface) (*Table
 	if err != nil {
 		return nil, err
 	}
-	tab, _ := newUDP(priv, conn, natm)
+	tab, _ := newUDP(priv, conn, natm, seedCache)
 	glog.V(logger.Info).Infoln("Listening,", tab.self)
 	return tab, nil
 }
 
-func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface) (*Table, *udp) {
+func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, seedCache string) (*Table, *udp) {
 	udp := &udp{
 		conn:       c,
 		priv:       priv,
@@ -176,7 +176,7 @@ func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface) (*Table, *udp) {
 			realaddr = &net.UDPAddr{IP: ext, Port: realaddr.Port}
 		}
 	}
-	udp.Table = newTable(udp, PubkeyID(&priv.PublicKey), realaddr)
+	udp.Table = newTable(udp, PubkeyID(&priv.PublicKey), realaddr, seedCache)
 	go udp.loop()
 	go udp.readLoop()
 	return udp.Table, udp
diff --git a/p2p/server.go b/p2p/server.go
index ecf418d13..39b0b8b6e 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -59,6 +59,10 @@ type Server struct {
 	// with the rest of the network.
 	BootstrapNodes []*discover.Node
 
+	// SeedCache is the path to the database containing the previously seen live
+	// nodes in the network to use as potential bootstrap seeds.
+	SeedCache string
+
 	// Protocols should contain the protocols supported
 	// by the server. Matching protocols are launched for
 	// each peer.
@@ -197,7 +201,7 @@ func (srv *Server) Start() (err error) {
 	}
 
 	// node table
-	ntab, err := discover.ListenUDP(srv.PrivateKey, srv.ListenAddr, srv.NAT)
+	ntab, err := discover.ListenUDP(srv.PrivateKey, srv.ListenAddr, srv.NAT, srv.SeedCache)
 	if err != nil {
 		return err
 	}